Seven aphid species were collected from almond trees in Najafabad and identified. Sexual females (oviparae) of Rhopalosiphum padi (L.) were collected from almond trees in fall, being the first report. Pterochloroides persicae, Brachycaudus amygdalinus (Schout.) and Hyalopterus amygdali (Blanch.) were the most common species and their injuries the most pronounced, hence they were considered as dominant species. Seasonal population fluctuation of P. persicae on almond was studied, including times of egg hatch, spring and fall outbreak, appearance and dispersal of winged forms, summer activity, oviposition, and number of eggs, overwintering situation as well as other host plants. The results indicated that brown peach aphid eggs hatched and nymph colonies were produced on 20-22 Feb. In late April alate forms appeared. Aestivating aphids were seen in orchards with humid conditions. Fall colonies appeared in late Sep. with their numbers and populations increasing rapidly. In mid Nov. oviparae appeared with each oviparous female producing 9.2 ± 1.5 eggs.
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